Fuel pressure variations in a compression ignition (diesel) engine can give important information about the running of the engine and possible adjustments and repairs. It is in the highest degree undesirable to interfere with the integrity of the fuel lines. This conditions makes it difficult to obtain suitable pressure-dependent signals for analysis.
The invention aims to provide simple and effective pressure-sensing devices suitable for a variety of engine arrangements and means to analyse signals from such devices to provide a record or display helpful to engineers investigating the performance of such engines.
However the pressure sensing devices can be adapted to various other uses, such as sensing cyclic variations in pump delivery pressure.